Native inline HTML syntax for Python

This is an idea I've had for a while and unfortunately it turns out to be possible: JSX for Python.

It works without (explicit) transpilation in pure native python and supports custom components and state updates.

Example

Depending on your font, the characters may render strangely. But it's valid python code and that's all the interpreter cares about!

class Main(Component):
    """
    Demo Application Component

    This app demonstrates the 'cursed' inline html syntax with
    a classic click counter app.
    """

    def get_initial_state(self):
        return {
            "count": 0,
            "color": "#000000",
        }
    
    def render(self):
        def increment():
            self.set_state({
                "count": self.state["count"] + 1,
            })
        
        def pick_color():
            from tkinter import colorchooser
            self.set_state({
                "color": colorchooser.askcolor(title="Pick a color")[1],
            })

        return ᐸframeᐳ
        ㅤㅤㅤㅤㅤᐸlabelㅤforegroundꘌײ(self.state.color),ײᐳCurrentㅤcountㅤisㅤ(self.state.count),ᐸ𐤕labelᐳ
        ㅤㅤㅤㅤㅤᐸbuttonㅤcommandꘌײ(increment),ײᐳIncrementᐸ𐤕buttonᐳ
        ㅤㅤㅤㅤㅤᐸbuttonㅤcommandꘌײ(pick_color),ײᐳChangeㅤtextㅤcolorᐸ𐤕buttonᐳ
        ᐸ𐤕frameᐳ

Running

This project has no third-party dependencies so running it is as simple as cloning and executing the main.py script.

git clone git@github.com:AwdeDarkar/cursed-python-html.git
cd cursed-python-html
python3 ./main.py

How It Works

Basically there are a few key ideas underlining this demo: weird unicode characters that python treats as letters but that look like symbols, overriding the sys.excepthook to recover from NameErrors, and 'in-place' transpiling.

Essentially, the HTMLish syntax looks like tuples of unbound variables to python. When the interpreter encounters them, it raises a NameError that we can detect and use to re-run the source file with corrected code.

Limitations

There are a few known problems:

• State in sub-components is lost when a parent re-renders
• Custom components must all be in the same file
• Re-renders unmount and recreate the whole widget tree from parent down, causing occasional flashes on updates.
• The file in which the HTMLish syntax appears is run twice, along with any side-effects

These are bugs that I could fix, but I probably won't because no one should actually use this for anything and there's really only so much effort I'm willing to invest in this farce.

Why???

This nightmare of an idea crawled into my head when I read about someone using characters from the Canadian Aboriginal Syllabics block to fake generics in Go.

Mainly, I did this just to see if I could.